Some (hopefully) exciting news: The Mirror's Surface Breaks version 1.3 is now available. Here are the highlights:

• The Windows® version now includes a 64-bit version of the DaVinci's Shadow script processor (in addition to a 32-bit version like earlier releases). This essentially does away with any limitations on image size, as long as the PC where it's being run has enough physical memory. A 64-bit version of Windows® is required, of course.
• It is now possible to use TMSB on Linux and BSD! This requires more effort to set up than using it on Windows® - see DaVinci's Shadow Build Process - Linux, DaVinci's Shadow Build Process - BSD, and TMSB on Unix-like Operating Systems. There are screenshots in the main The Mirror's Surface Breaks article.
• All of the improvements from versions 1.2.1 and 1.2.2 are included.

If you give it a try, please let me know how well it works for you.